Combined oil and water separator in an air brake dryer

ABSTRACT

A filter assembly for separating and removing a liquid from a compressed fluid stream includes a filter element for separating the liquid from the fluid, a purge valve, and an elongated valve operator for actuating the purge valve. The top of the filter element has a shroud that decreases the flow area of the entering fluid stream to induce a vortex of the fluid, allowing the liquid to separate from the fluid. The purge valve is located at the bottom of the filter element for draining the separated liquid. The elongated valve operator axially extends through the filter element and is moveable by an actuating piston located at the top of the filter element, in response to elevated pressure in the filter assembly. The filtered air is dried through a desiccant body and then outputted from the filter assembly to be used in an air brake system.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/069,380 filed Oct. 28, 2014, which is hereby incorporated herein byreference.

FIELD OF INVENTION

The present invention relates to vehicle air brake systems, and moreparticularly to air filters in vehicle air brake systems.

BACKGROUND OF THE INVENTION

Air brake systems are used in trucks or other heavy duty vehicles forproviding “failsafe” vehicle brake operation. Generally, air brakesystems have two modes of operating. The first mode is a failsafe modeused for the emergency brake function. The second mode is used undernormal operation and compressed air to activate the braking mechanism.If a loss of compressed air pressure occurs, the failsafe mechanismsengage the brakes attempting to lock the wheels in position and stop theprogress of the vehicle. Under normal operation, air that is compressedby a compressor in the vehicle is directed by the vehicle operator toactuators. The actuators are induced to move by the delivered compressedair. When the intended results are achieved and the braking function isno longer needed, the system exhausts the contained pressure within theactuator. The actuator returns to the original position and the brakingmechanisms are disengaged. Thus, the compressed air provides andmaintains air under pressure to the brakes to ensure fails-safe vehiclebrake operation.

The compressed air that leaves the compressor is typically not suitableto be supplied directly to the brake system for several reasons. Thefirst reason is that the compressed air contains oil. The compressor issupplied with oil from the vehicle engine that is used for lubricationof bearings and other compressor components. Lubricating oil within thecompressor is difficult to contain. It contaminates the compressed airstream delivered by the compressor. The second reason is that thecompressor ingests humid air from the surrounding environment. The humidair is compressed and delivered by the compressor to the system.

Conventional air brake systems use a dryer located downstream of the aircompressor to dry the pressurized air prior to delivery of the air tothe brakes. The air is dried for efficiency and to prevent damage to thedownstream components. However, the dryer typically houses a desiccantmaterial that may become contaminated with the oil entrained in thecompressed air. Thus, an improved filter assembly is desirable.

SUMMARY OF THE INVENTION

A filter assembly according to the present invention includes acentrifugal pre-separator for a filter element, within an air dryer. Thecentrifugal pre-separation is achieved using an interface between amanifold head, a filter element housing, and a filter element end cap.The endcap has a shroud at a top end of the filter element. The shroudis configured to radially accelerate air that has been compressed into avortex while entering the filter assembly, allowing the oil and water toseparate from the vortex. The filtered air enters a desiccant body andis dried before being outputted from the filter assembly for use in abrake system. The efficacy and the functional life of a desiccant mediumof the filter assembly are improved when the oil is separated prior toreaching the desiccant medium.

A purge valve is also provided at a bottom end of the filter element fordraining the separated oil and water from the filter assembly. The purgevalve is actuated when a pressure signal is communicated from acompressor to a port in the filter assembly. The pressure signalactivates an elongated valve operator axially extending through thefilter element between the top end and the bottom end.

A filter element for separating a liquid from a compressed fluid streamthat flows into the filter element includes a longitudinally extendingbody of coalescing media having a first end and a second end distallyopposite the first end, and a first end cap having a central bodyportion fixed to the first end of the body of coalescing media. Thefirst end cap also includes a shroud that extends longitudinally fromthe central body portion and has a radially outer annular surface thatprogressively increases in diameter from a first end of the shroud to asecond end of the shroud in a direction toward the second end of the ofbody of coalescing media. The shroud is configured to reduce a flow areaof the fluid stream flowing into the filter element to induce a vortexof the fluid around the body of coalescing media, allowing the liquid toseparate from the vortex.

A filter element for separating and removing a liquid from a fluidincludes a longitudinally extending body of coalescing media forseparating the liquid from the fluid having a top end and a bottom enddistally opposite the top end, and a purge valve assembly at the bottomend of the body of coalescing media. The purge valve assembly has apurge valve that is biased in a closed position and moveable to an openposition to drain the liquid out of the filter assembly.

A filter assembly for separating and removing a liquid from a fluidincludes a filter head having a fluid inlet and an actuating piston, alongitudinal filter element for separating the liquid from the fluidthat has a first end in fluid communication with the fluid inlet and asecond end distally opposite the first end, a purge valve at the secondend of the filter element distally opposite the filter head that isbiased in a closed position and moveable to an open position fordraining the liquid out of the filter assembly, and an elongated valveoperator that axially extends through the filter element between thefirst end and the second end and is configured to move the purge valvebetween the closed position and the open position. The actuating pistonis configured to move the purge valve by acting on the valve operator,in response to elevated pressure in the filter assembly.

These and further features of the present invention will be apparentwith reference to the following description and attached drawings. Inthe description and drawings, particular embodiments of the inventionhave been disclosed in detail as being indicative of some of the ways inwhich the principles of the invention may be employed, but it isunderstood that the invention is not limited correspondingly in scope.Rather, the invention includes all changes, modifications andequivalents coming within the spirit and terms of the claims appendedhereto. Features that are described and/or illustrated with respect toone embodiment may be used in the same way or in a similar way in one ormore other embodiments and/or in combination with or instead of thefeatures of the other embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing depicting a perspective view of a filter assembly.

FIG. 2 is a drawing depicting an exploded view of the filter assembly inFIG. 1 showing a filter element.

FIG. 3 is a drawing depicting a cross-sectional view of the filterelement in FIG. 2.

FIG. 4 is a drawing depicting a perspective view of a desiccant body ofthe filter element in FIG. 3.

FIG. 5 is a drawing depicting a cross-sectional view of an endcap of thefilter element in FIG. 3.

FIG. 6 is a drawing depicting a cross-sectional view of the filterassembly in FIG. 1.

DETAILED DESCRIPTION

The principles of the present invention have particular application inheavy duty vehicles such as trucks and work vehicles having air brakesystems. The air brake system includes a compressor for pressurizing airthrough fluid lines that supply the fluid to brakes of the vehicle. Thecompressor is configured to generate a body of fluid containing air,oil, and water and is in fluid communication with a dryer assembly swirlchamber. The swirl chamber is in fluid communication with a filterassembly that separates the oil and bulk water from the body of fluidand dries the filtered air, such that clean and filtered air exits thefilter assembly and is supplied to the brakes.

Referring first to FIGS. 1 and 2, a filter assembly 10 is used in an airbrake system. The exemplary filter assembly 10 may include a filter head12 and a filter housing 14 attached to the filter head 12 via bolts 16and bolt holes 18 formed in the filter head 12. The filter head 12 maybe formed of a cast metal and may include a mounting portion 20 withmounting holes 22 that are slotted or round for mounting the filterassembly 10 within a vehicle (not shown). The filter head 12 defines acompressed fluid inlet 24 that is in fluid communication with acompressor (not shown) of the vehicle. The fluid inlet 24 may bespiral-shaped such that a compressed fluid stream of air containing oiland water enters the filter housing 14 from the fluid inlet 24. Thefilter head 12 also includes a fluid outlet 26 that outputs the filteredfluid, which generally is clean and dry air, from the filter assembly 10to be used in operation of the brake system (not shown). The fluidoutlet 26 is in sealed fluid communication with the brake system.

The filter housing 14 may be tubular with a first end 28 and a secondend 30. The first end 28 is attachable to the filter head 12 and thesecond end 30 has a purge port 32 for draining the filtered oil andwater from the filter assembly 10. The purge port 32 contains a purgeassembly (described in more detail below) that is actuated in responseto a governor control port 34 located in the filter head 12. Thegovernor control port 34 governs the maximum pressure in the filterassembly 10 based on signals sent by the compressor of the vehicle. Thecompressor sends a signal that the amount of pressure entering thefilter assembly 10 is at a maximum and the signal is conducted to thegovernor control port 34. The governor control port 34 further isconfigured to operate a piston that in turn opens the purge valve withinthe purge assembly. The open purge valve allows the fluid to drain fromthe filter assembly 10 and into the surrounding environment.

FIG. 2 is a drawing depicting an exploded view of the filter assembly 10shown in FIG. 1. The filter assembly 10 includes a filter element 36received in the filter housing 14 for separating the liquid from thecompressed fluid. The filter element 36 may be a replaceablecartridge-style element, and has a longitudinally extending body ofcoalescing media 38. The filter element 36 may be easily removable fromthe filter housing 14 for servicing and replacement. The filter element36 is inserted into the filter housing 14 such that the body of fluid istrapped between the filter housing 14 and the body of coalescing media38. The oily and humid air from the body of fluid enters the body ofcoalescing media 38, allowing oil droplets and moisture to coalesce intolarger droplets. As the oil and/or moisture droplets grow in size, thedroplets form a layer separable from the fluid.

The filter element 36 may further include a first end cap 40 having acentral body portion 42 that is attachable to the filter head 12 andfixed to a first end 44 of the body of coalescing media 38. The firstend cap 40 includes a shroud 46 that extends longitudinally from thecentral body portion 42. The shroud 46 has a radially outer annularsurface 48 that progressively increases in diameter from a first end 47toward a second end 49 of the shroud 46. The body of coalescing media 38further includes a second end 50 that is located distally opposite thefirst end 44. In the exemplary filter element 36, the first end 44 is atop end and the second end 50 is a bottom end. The annular surface 48 ofthe shroud 46 may be continuous and flare radially outwardly from thebody of coalescing media 38 toward the filter housing 14. The shroud 46is configured to reduce the flow area of the entering stream ofcompressed fluid from the spiral-shaped fluid inlet 24. The areareduction induces a vortex within the filter housing 14, allowing theliquid to separate from the vortex of air as the vortex of fluid swirlsaround the body of coalescing media 38. The spiral-shaped fluid inlet 24and the shroud 46 induce the vortex which provides the centrifugalpre-separation of the liquid particles of oil and water. The oil andwater are separated from the fluid prior to coalescing and furtherseparated by the coalescing medium prior to desiccation.

Referring in addition to FIG. 3, the outer annular surface 48 of theshroud 46 is spaced radially outwardly from the body of coalescing media38, defining a recess 52 between the outer annular surface 48 and thebody of coalescing media 38. The recess 52 increases in diameter fromthe first end 47 of the shroud 46 toward the second end 49 of theshroud. The outer annular surface 48 may be convexed in the longitudinaldirection. The shroud 46 may be mushroom-shaped or frustoconical. Theshroud 46 also has a planar surface 54 that extends radially outwardlyfrom the central body portion 42 to the outer annular surface 48. Theplanar surface 54 may have at least one axially extending surface 56that are received within the body of coalescing media 38 for furthersecuring the shroud 46 to the first end 44 of the body of coalescingmedia 38. The axially extending surface 56 may be a wall that isannular. The wall may be thin. The axially extending surface 56 may be aplug.

The body of coalescing media 38 may be tubular. The body of coalescingmedia 38 may be pleated or have any shape suitable for use within thefilter assembly 10. The body of coalescing media 38 may have an outerwall 58 circumscribing a central cavity 60. Referring in addition toFIG. 4, the filter element 36 further includes a longitudinal desiccantbody 62 extending through the central cavity 60 between the first end 44and the second end 50 of the body of coalescing media 38. The desiccantbody 62 has a top end at the first end 44 and a bottom end at the secondend 50. The desiccant body 62 may be surrounded by a steel tube 64. Whenliquid is separated from the vortex, the separated liquid and air flowsdownwardly through the central cavity 60 from the first end 44 to thesecond end 50 of the body of coalescing media 38. The filtered air canthen enter the desiccant body 62 at the second end 50 for drying. Thefilter element 36 further includes a second end cap 66 at the second end50 of the body of coalescing media 38 that defines a fluid passage 67.The fluid passage 67 allow oil-free air to wrap around a bottom end ofthe desiccant body 62 and the steel tube to enter the desiccant body 62at the bottom end of the desiccant body 62. The separated oil does notreach the desiccant body 62. The second end cap 66 may further includean axially extending rim 68 that extends from the second end cap 66within the central cavity 60 for supporting the desiccant body 62, thetube 64, and the elongated valve operator 82 within the body ofcoalescing media 38.

The second end cap 66 also includes a purge valve assembly 69 fordraining the filtered water and oil from the filter assembly 10. Thepurge valve assembly 69 is housed in the purge port 32 of the filterhousing 14 and includes a purge valve 70. The purge valve 70 is biasedby a spring 72 to a closed position and is moveable to an open positionfor draining the liquid. The purge valve 70 may be a poppet style valve.The purge valve assembly 69 also includes a sump 74 for holding orretaining the liquid within the filter assembly 10 when the purge valve70 is in the closed position. The sump 74 may be cone-shaped. Theseparated liquid is deposited in the sump 74. The purge valve assembly69 further includes a valve seat 76 defined by the sump 74 against whichthe purge valve 70 is seated when in the closed position. The sump 74directs the collected oil and water to a mouth of the purge valve 70.The second end cap 66 further includes a central body portion 78 inwhich the purge valve assembly 69 is contained. The second end cap 66also has a radially extending flange 80 for attaching the second end cap66 to the second end 50 of the body of coalescing media 38. The secondend cap 66 may also have a snap ring 81 for securing the purge valveassembly 69 within the second end cap 66.

The purge valve 70 may be actuated by an elongated valve operator 82that axially extends through the desiccant body 62 between the first end44 and the second end 50 of the body of coalescing media 38. The valveoperator 82 is configured to move the purge valve 70 to the openposition when the valve operator 82 is depressed. The valve operator 82may protrude from the desiccant body 62 at the second end 50 of the bodyof coalescing media 38. The valve operator 82 engages a head 84 of thepurge valve 70 through the second end cap 66 at the second end 50 of thebody of coalescing media 38. The valve operator 82, the desiccant body62, and the body of coalescing media 38 may be concentrically positionedabout a longitudinal axis of the filter assembly 10.

Referring in addition to FIG. 5, the valve operator 82 may also protrudefrom the top end of the desiccant body 62 at the first end 44 of thebody of coalescing media 38. The valve operator 82 may extend throughand further protrude from the central body portion 42 of the first endcap 40. The central body portion 42 may define an axially extendingchamber 86 that extends into the desiccant body 62. The chamber 86 andthe desiccant body 62 may be coaxial. The valve operator 82 may includea radially extending limit stop 88 that travels within the chamber 86such that the chamber 86 defines the movement of the valve operator 82.The central body portion 42 may define a fluid outlet 90 and at leastone outlet passage 92 in fluid communication with the desiccant body 62.The at least one outlet passage 92 may include a plurality of outletpassages and allows the filtered and dried air to flow out of thedesiccant body 62 and into the fluid outlet 90. The fluid outlet 90 maybe in fluid communication with the filter head 12 for outputting thefiltered air from the filter element 36.

Referring now to FIG. 6, a filter assembly 10 includes a filter head 12and a filter housing 14 receiving a filter element 36. FIG. 6 shows theentire filter assembly in cross-section, and therefore like componentsare identified by like reference numerals in FIGS. 1-6. The filter head12 includes a spiral-shaped fluid inlet 24 and a fluid outlet 26. Fluidenters the filter assembly 10 via the fluid inlet 24. The fluid iscompressed by a compressor (not shown) that outputs a fluid containing amixture of air, oil, and water. The filter element 36 may be areplaceable element and is cartridge-like for inserting the filterelement 36 within the filter housing 14 and removing the filter element36 for servicing and replacement. The filter element 36 has alongitudinally extending body of coalescing media 38 having a first end44 and a second end 50 distally opposite the first end 44. The filterelement 36 has a top end cap 40 that has a central body portion 42 fixedto the first end 44 of the body of coalescing media 38. The top end cap40 has a shroud 46 that extends longitudinally from the central bodyportion 42 and has a radially outer annular surface 48 thatprogressively increases in diameter from the first end 47 toward thesecond end 49 of the shroud 46. The shroud 46 is configured to reduce aflow area of the entering stream of compressed fluid to induce a vortexof fluid. The vortex swirls around the body of coalescing media 38,between the filter housing 14 and the body of coalescing media 38.

The body of coalescing media 38 is tubular and has an outer wallcircumscribing a central cavity 60. A desiccant body 62 extends axiallythrough the central cavity 60 between the first end 44 and the secondend 50 of the body of coalescing media 38. The separated liquid andfiltered air travels within the central cavity 60 from the first end 44toward the second end 50. The filtered air enters the desiccant body 62at the second end 50 to be dried. Once the filtered air has traveled tothe top of the desiccant body 62, the filtered air passes through aplurality of o-ring passages 92 defined in the top end cap 40. Thefiltered air is then outputted from the filter assembly 10 through afluid outlet 26 having sealed fluid communication with the plurality ofo-ring passages 92, to be used in a brake system. The fluid outlet 26may include a check valve assembly (not shown).

The liquid is drained from the fluid assembly 10 via a purge valveassembly 69 located at the second end 50 of the body of coalescing media38. The purge valve assembly 69 is housed in a purge port 32 of thefilter housing 14 and includes a purge valve 70. The purge valve 70 isbiased by a spring 72 to a closed position and is moveable to an openposition for draining the liquid. The purge valve assembly 69 alsoincludes a sump 74 for retaining the liquid within the filter assembly10 when the purge valve 70 is in the closed position. The sump 74 may becone-shaped. The purge valve assembly 69 further includes a valve seat76 defined by the sump 74 against which the purge valve 70 is seatedwhen in the closed position. The purge valve assembly 69 may becontained in a bottom end cap 66 of the filter element 36 located at thesecond end 50 of the body of coalescing media 38.

The purge valve 70 is actuatable by an elongated valve operator 82 thataxially extends through the desiccant body 62 between the first end 44and the second end 50 of the body of coalescing media 38. The valveoperator 82 is configured to move the purge valve 70 to the openposition when the valve operator 82 is depressed. The valve operator 82may protrude from the desiccant body 62 at the first end 44 and thesecond end 50 of the body of coalescing media 38. The valve operator 82engages the head 84 of the purge valve 70 at the second end 50. Thevalve operator 82, the desiccant body 62, and the body of coalescingmedia 38 may be positioned concentrically about a longitudinal axis ofthe filter assembly 10. The valve operator 82 and the purge valve 70 mayalso be replaceable when replacing the filter element 36 in the filterassembly 10.

The valve operator 82 is configured to move the purge valve 70 betweenthe closed position and the open position. The valve operator 82 ismoveable by an actuating piston 94 located in the filter head 12,distally opposite the purge valve assembly 69. The actuating piston 94moves the purge valve 70 by acting on the valve operator 82, in responseto the elevated pressure signal communicated by the compressor (notshown) to the governor control port 34 in the filter assembly 10. Thefilter head 12 includes an atmospheric reference chamber 96 in which theactuating piston is axially moveable and that is separated from thegovernor control port 34 by the actuating piston 94. When the compressorsends a signal that the pressurized air in the filter assembly 10 is ata maximum pressure, the governor control port 34 is filled withcompressed air. The elevated pressure acts upon the piston 94. Thepiston 94 is then depressed against the atmospheric reference chamber 96and a piston return spring 100. The piston return spring 100 iscompressed with the spring 72 of the purge valve assembly 69. The pistonreturn spring 100 returns the piston 94 to its normal position when thepressure signal at the governor control port 34 is removed. The piston94 is depressed to move the valve operator 82 against the force of thereturn spring 100 and the spring 72 and open the purge valve 70 to drainthe liquid from the filter assembly 10. A radially extending limit stop88 limits the return travel of the operator 82. The limit stop 88 alsoretains the operator from unintended removal from the first end cap 40when the filter element 36 is not installed within the filter assembly10. The drained liquid is emitted to the surrounding environment of thevehicle.

A filter element for separating a liquid from a compressed fluid streamthat flows into the filter element includes a longitudinally extendingbody of coalescing media having a first end and a second end distallyopposite the first end, and a first end cap having a central bodyportion fixed to the first end of the body of coalescing media. Thefirst end cap has a shroud that extends longitudinally from the centralbody portion and has a radially outer annular surface that progressivelyincreases in diameter from a first end of the shroud to a second end ofthe shroud in a direction toward the second end of the of body ofcoalescing media. The shroud is configured to reduce a flow area of thefluid stream flowing into the filter element to induce a vortex of thefluid around the body of coalescing media, allowing the liquid toseparate from the vortex.

The outer annular surface may be spaced radially outwardly from the bodyof coalescing media or convexed in the longitudinal direction. Theshroud may be mushroom-shaped or frustoconical. The shroud may have aplanar surface extending radially outwardly from the central bodyportion to the outer annular surface.

The filter element may be inserted into a tubular housing such that thevortex is trapped between the tubular housing and the body of coalescingmedia. The annular surface of the shroud may flare radially outwardlyfrom the body of coalescing media toward the tubular housing.

The body of coalescing media may be tubular and have an outer wallcircumscribing a central cavity. The filter element may include alongitudinal desiccant body axially extending through the centralcavity. The central body portion of the first endcap may define at leastone outlet passage in fluid communication with the desiccant body thatallows the filtered air to flow out of the desiccant body through the atleast one outlet passage.

The filter element may include a second end cap at the second end of thebody of coalescing media that has a purge valve biased in a closedposition that is moveable to an open position to drain the liquid out ofthe filter assembly. The filter element may further include an elongatedvalve operator axially extending through the body of coalescing mediabetween the first end and the second end. The valve operator may beconfigured to move the purge valve to the open position when the valveoperator is depressed.

The filter element may be included in a filter assembly that has aspiral-shaped fluid inlet such that the shroud is configured to reducethe flow area of the fluid stream from the fluid inlet into the filterelement, to induce the vortex of the fluid.

A filter element for separating and removing a liquid from a fluidincludes a longitudinally extending body of coalescing media forseparating the liquid from the fluid having a top end and a bottom enddistally opposite the top end, and a purge valve assembly at the bottomend of the body of coalescing media, wherein the purge valve assemblyhas a purge valve biased in a closed position and moveable to an openposition to drain the liquid out of the filter assembly.

The purge valve assembly may include a sump for holding the liquid whenthe purge valve is in the closed position, and a valve seat defined bythe sump against which the purge valve is seated when in the closedposition. The filter element may further include an elongated valveoperator axially extending through the body of coalescing media betweenthe top end and the bottom end, such that the elongated valve operatoris configured to move the purge valve between the closed position andthe open position.

A filter assembly for separating and removing a liquid from a fluidincludes a filter head having a fluid inlet and an actuating piston, alongitudinal filter element for separating the liquid from the fluidthat has a first end in fluid communication with the fluid inlet and asecond end distally opposite the first end, a purge valve at the secondend of the filter element distally opposite the filter head that isbiased in a closed position and moveable to an open position fordraining the liquid out of the filter assembly, and an elongated valveoperator that axially extends through the filter element between thefirst end and the second end and is configured to move the purge valvebetween the closed position and the open position. The actuating pistonis configured to move the purge valve by acting on the valve operator,in response to elevated pressure in the filter assembly.

The filter head may include an atmospheric reference chamber in whichthe actuating piston is moveable and that is configured to detect whenthe filter assembly has elevated pressure. The filter head may include agovernor pressure chamber that is separated from the atmosphericreference chamber by the actuating piston, such that the piston moveswhen elevated pressure is communicated to the governor pressure chamber.

The fluid inlet may be spiral-shaped and the filter element may beconfigured to reduce a flow area of fluid entering the filter elementfrom the fluid inlet, to induce a vortex of the fluid. The filterassembly may include a shroud at the first end of the filter elementthat extends longitudinally from a first end toward a second end of theshroud and has a radially outer annular surface that progressivelyincreases in diameter from the first end toward the second end of theshroud, such that the shroud is configured to induce the vortex andaccelerate a speed of the vortex, allowing the liquid to separate fromthe vortex. The shroud may include at least one outlet passage at thefirst end of the filter element allowing filtered air to exit the filterelement. The filter head may include a fluid outlet in fluidcommunication with the at least one outlet passage at the first end ofthe filter element.

The filter element may further include a sump at the second end of thefilter element and a valve seat defined by the sump, such that the purgevalve is biased against the valve seat when in the closed position.

The filter element may include a longitudinal body of coalescing mediacircumscribing a central cavity, and a longitudinal desiccant bodywithin the central cavity. The elongated valve operator may extendthrough the desiccant body and protrudes from the desiccant body at thefirst end and the second end of the filter element.

Although the invention has been shown and described with respect to acertain embodiment or embodiments, it is obvious that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described elements (components, assemblies, devices, compositions,etc.), the terms (including a reference to a “means”) used to describesuch elements are intended to correspond, unless otherwise indicated, toany element which performs the specified function of the describedelement (i.e., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary embodiment or embodimentsof the invention. In addition, while a particular feature of theinvention may have been described above with respect to only one or moreof several illustrated embodiments, such feature may be combined withone or more other features of the other embodiments, as may be desiredand advantageous for any given or particular application.

What is claimed is:
 1. A filter element for separating a liquid from acompressed fluid stream that flows into the filter element, the filterelement comprising: a longitudinally extending body of coalescing mediahaving a first end and a second end distally opposite the first end; anda first end cap having a central body portion fixed to the first end ofthe body of coalescing media, and a shroud that extends longitudinallyfrom the central body portion and has a radially outer annular surfacethat progressively increases in diameter from a first end of the shroudto a second end of the shroud in a direction toward the second end ofthe of body of coalescing media, wherein the shroud is configured toreduce a flow area of the fluid stream flowing into the filter elementto induce a vortex of the fluid around the body of coalescing media,allowing the liquid to separate from the vortex.
 2. The filter elementaccording to claim 1, wherein the outer annular surface is spacedradially outwardly from the body of coalescing media.
 3. The filterelement according to claim 1, wherein the shroud has a planar surfaceextending radially outwardly from the central body portion to the outerannular surface.
 4. The filter element according to claim 1, wherein theouter annular surface is convexed in the longitudinal direction.
 5. Thefilter element according to claim 1, wherein the shroud ismushroom-shaped.
 6. The filter element according to claim 1, wherein theshroud is frustoconical.
 7. The filter element according to claim 1,wherein the body of coalescing media is tubular and has an outer wallcircumscribing a central cavity.
 8. The filter element according toclaim 7 further comprising: a longitudinal desiccant body axiallyextending through the central cavity.
 9. The filter element according toclaim 8, wherein the central body portion of the first endcap defines atleast one outlet passage in fluid communication with the desiccant bodythat allows the filtered air to flow out of the desiccant body throughthe at least one outlet passage.
 10. The filter element according toclaim 1 further comprising: a second end cap at the second end of thebody of coalescing media having a purge valve that is biased in a closedposition and moveable to an open position to drain the liquid out of thefilter assembly.
 11. The filter element according to claim 10 furthercomprising: an elongated valve operator axially extending through thebody of coalescing media between the first end and the second end,wherein the valve operator is configured to move the purge valve to theopen position when the valve operator is depressed.
 12. A filterassembly comprising: the filter element according to claim 1; and atubular housing, wherein the filter element is inserted into a tubularhousing and the vortex is trapped between the tubular housing and thebody of coalescing media.
 13. The filter assembly according to claim 12,wherein the annular surface of the shroud flares radially outwardly fromthe body of coalescing media toward the tubular housing.
 14. A filterassembly comprising: the filter element according to claim 1; and aspiral-shaped fluid inlet, wherein the shroud is configured to reducethe flow area of the fluid stream from the fluid inlet into the filterelement, to induce the vortex of the fluid.
 15. A filter element forseparating and removing a liquid from a fluid comprising: alongitudinally extending body of coalescing media for separating theliquid from the fluid having a top end and a bottom end distallyopposite the top end; and a purge valve assembly at the bottom end ofthe body of coalescing media, wherein the purge valve assembly has apurge valve biased in a closed position and moveable to an open positionto drain the liquid out of the filter assembly, a sump for holding theliquid when the purge valve is in the closed position, and a valve seatdefined by the sump against which the purge valve is seated when in theclosed position.
 16. The filter element according to claim 15 furthercomprising: an elongated valve operator axially extending through thebody of coalescing media between the top end and the bottom end, whereinthe elongated valve operator is configured to move the purge valvebetween the closed position and the open position.
 17. A filter assemblyfor separating and removing a liquid from a fluid comprising: a filterhead having a fluid inlet and an actuating piston; a longitudinal filterelement for separating the liquid from the fluid that has a first end influid communication with the fluid inlet and a second end distallyopposite the first end; a purge valve at the second end of the filterelement distally opposite the filter head that is biased in a closedposition and moveable to an open position for draining the liquid out ofthe filter assembly; and an elongated valve operator that axiallyextends through the filter element between the first end and the secondend and is configured to move the purge valve between the closedposition and the open position, wherein the actuating piston isconfigured to move the purge valve by acting on the valve operator, inresponse to elevated pressure in the filter assembly.
 18. The filterassembly according to claim 17, wherein the filter head includes anatmospheric reference chamber and a governor pressure chamber that areseparated by the actuating piston, wherein the actuating piston ismoveable within the atmospheric reference chamber when elevated pressureis communicated to the governor pressure chamber.
 19. The filterassembly according to claim 17, wherein the fluid inlet is spiral-shapedand the filter element is configured to reduce a flow area of fluidentering the filter element from the fluid inlet, to induce a vortex ofthe fluid.
 20. The filter assembly according to claim 19 furthercomprising: a shroud at the first end of the filter element that extendslongitudinally from a first end toward a second end of the shroud andhas a radially outer annular surface that progressively increases indiameter from the first end toward the second end of the shroud, whereinthe shroud is configured to reduce the flow area of fluid to induce thevortex, and accelerate a speed of the vortex, allowing the liquid toseparate from the vortex.